Short-Term Nitrogen Leaching Potential Of Fresh and Composted Beef Cattle Manure Applied to Disturbed Soil Cores

摘要

Although fresh beef cattle (Bos taurus) manure has traditionally been applied to cropland in southern Alberta, there has been a recent increase in application of composted manure to cropland in this region. Nitrogen leaching from fresh manure (FM) versus composted (CM) beef cattle manure application has not been investigated in this region. Our objective was to compare short-term ( less than or equal to 23 d) N leaching potential of NO sub(3)-N and NH sub(4)-N under increasing rates (0, 13, 39, 77 Mg ha super(-1) dry wt.) of FM and CM applied to a clay loam soil under uniform soil and simulated environmental conditions. Amendments were applied and incorporated into repacked 15-cm soil (surface Ah horizon) cores, incubated for 15 d, and then leached under constant-head and saturated conditions in the laboratory. An unamended control (CON) was also used. Leaching potential of NO sub(3)-N and NH sub(4)-N depended on how the N leaching variable was expressed: peak concentration vs flow-weighted mean concentration (FWMC) vs mass loss vs recovery in leachate. Peak concentrations of NO sub(3)-N were at least 90% greater for CM (125.8 mg L super(-1)) than FM (66.3 mg L super(-1)) and the CON (60.5 mg L super(-1)) treatments. The FWMC of NO sub(3)-N was significantly (P less than or equal to 0.05) greater for CM (21.0 mg L super(-1)) than FM (16.3 mg L super(-1)). Recovery of NO sub(3)-N in leachate as a percentage of total N applied was significantly greater for CM (4.7%) than FM (0.8%). Peak concentrations of NH sub(4)-N, FWMC of NH sub(4)-N, mass loss of NO sub(3) and NH sub(4), and recovery of NH sub(4), were similar between FM and CM. These results suggest that short-term N leaching potential of CM was greater than FM for peak concentration, FWMC, and recovery of NO sub(3)-N.